Reference for Keritot 42:16

אילימא דחלבו מותר הרי חיה דחלבה מותר ודמה אסור

Said Abaye: It refers to its fluff whic is not subject to the law of kil'ayim.<span class="x" onmousemove="('comment',' The fluff of fowl may be woven together with linen.');">¹⁰</span>

Jastrow